Thermal circuit-closer



(N0 Modem H. F. MAXIM.

THERMAL CIRCUIT CLOSER.

No. 578,345. Patented Mar. 9, 1897.

UNITED STATES PATENT OFFICE.

I'IOSEA F. MAXI, OF NORFOLK, VIRGINIA.

THERMAL ClRCUiT-CLOSER.

SPECIFICATION forming part of Letters Patent No. 578,345, dated March 9, 1897.

Application filed May 29, 1896- To all whom it may concern.-

Be it known that I, IIOSEA F. MAXIM, a citizen of the United States, residing at Norfolk, in the county of Norfolk and State of Virginia, have invented certain new and useful Improvements in Thermal Circuit-Closers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to improvements in thermostatically-operated electric signaling mechanism, the object being to provide an apparatus bymeans of which an alarm or suitable signal will be actuated upon the temperature of an apartment reaching a certain degree or upon any sudden increase in temperature, as by the breaking out of a fire.

In the accompanying drawings, Figure 1 is an elevation of a thermostat embodying my improvements. Fig. 2 is a sectional view on the line 00 a: of Fig. 1.

In the drawings, A designates a supporting plate or board on which the various parts of the thermostat mechanism are mounted. On the base or supporting-plate A there is mounted a post B, which is electrically connected with a binding-post 0. About the post 13 is fitted a sleeve or short cylindrical piece D, which is electrically connected with a bind ing-post E, similar to that at O, the post B and cylinder D being insulated from each other by suitable non-conducting material F. The binding-posts G E are connected to opposite sides of an electric circuit which includes a battery G and bell or other alarm mechanism II. This latter may be of any suitable or desirable form and style.

To the post B is connected one end of a thermostat bar or rod I, which is preferably bent into spiral form, as shown, and is provided near its free end with a spring arm or finger 2 extending beyond one face of the rod, and a pin or stud t, projecting from the other opposite face or side. To the sleeve D is connected one end of another thermostat bar or rod K, similar in form and extending concentrically with the thermostat I. Near Serial No. 693,643. (No model.)

its outer end this bar K is provided with a projecting spring-finger 7a, which lies in the plane of and is adapted to contact with the stud or pin 2" on the thermostat I.

L designates a plate which is provided at one end with a sleeve Z, adapted to fit snugly about the sleeve D, such plate being of such material as to have electric connection with said sleeve D and therethro ugh with the binding-post E.

The plate L, which is preferably made in the form of a sector of a circle, is provided on one face with a series of graduations Z, marked to indicate degrees of temperature, and said plate is held in any desired position with relation to a stationary finger or pointer M by means of a screw N, which extends through a slot 02, formed in the plate, into the support or base A.

On the plate L is mounted a contact 0, it being preferably carried by a threaded rod 0, that extends through a suitable passage in a post 0 and by means of which said contact can be adjusted toward and from the contact 1' on the thermostat I.

As above stated and as shown in the drawings, the two thermostats I K are of the same form, and they are also of the same or substantially the same length. The thermostat I, however, contains more metal, it being thicker, and it therefore responds somewhat more slowly to the action of heat. In case there is a gradual rise in the temperature of the apartment in which the thermostats are placed the free ends of both will be moved toward the relatively stationary contact 0. As described, this contact is ad j ustable toward and from the contact '1 whereby the action of the apparatus can be readily controlled. XVhen, however, the maximum temperature is reached, the contact i on the thermostat I will contact with thecontact O and close the electric circuit through the plate L, sleeve D, post 0, through the signal mechanism H, battery G, post B, and thermostat I.

It will be seen that the contact 1' has to move through a relatively long path, and in event of a fire breaking out, causing a sudden rise in the temperature of the apartment, considerable time must elapse before the contact i would come into contact with the stationary contact. This would allow the fire to make dangerous headway, and in order to almost instantly sound an alarm on the breaking out of a tire I provide the additional quick-acting thermostat-bar Kthat is, in event of such a sudden increase in temperature the more sensitive thermostat K will move more rapidly than that at I, and the spring-finger thereof will contact with the stud or pin 1" and thereby close the electric circuit through the thermostat I, the post B, post 0, signal-mechanism post E, sleeve D, and thermostat K before the other bar I has come into contact with the stationary con tact 0. By the above it will be seen that I am enabled to so adjust the parts that an alarm will not be sounded under a gradual rise in temperature until a much higher degree has been reached than is indicated by thermostats as ordinarily constructed; and at the same time I provide for sounding an alarm in case of a sudden increase in temperature in less time than is required for the gradually-moving bar to come into contact with its coacting stationary contact. As soon as the temperature in the room decreases the contact between the thermostats or between the thermostat I and contact 0 is broken and the parts return to their normal positions.

lVhat I claim is- 1. In an electric signaling apparatus, the combination with signaling mechanism, and a relatively stationary contact connected with one terminal of an electric circuit, of two thermostats arranged in said circuit, one of which is adapted to close a circuit through the signaling mechanism either by contact with the other thermostat or by contact with the relatively stationary contact, substantially as set forth.

2. In an electric signaling apparatus, the combination with a signal or alarm mechanism, and a relatively stationary contact connected with one terminal of an electric circuit which includes the signal mechanism, of two thermostats connected with opposite sides of said circuit and both arranged to move toward the relatively stationary contact, said thermostats being of differentresistance, substantially as and for the purpose set forth.

3. In an electric signaling apparatus, the combination with a signal or alarm mechanism and a relatively stationary contact connected with one terminal of an electric circuit including the signal mechanism, of a thermostat connected with the other terminal of said circuit and adapted to contact with the rela tively stationary contact, and a second thermostat connected with the same terminal of the circuit as the relatively stationary contact and moving in a path parallel to the first said thermostat, said thermostats being of different resistances whereby on a sudden increase in temperature the more sensitive one will contact with the less sensitive one and thereby close a circuit through the signal mechanism independently of the relatively stationary contact, substantially as set forth.

4c. In an electric signaling apparatus, the combination with a signal or alarm mechanism, and a relatively stationary contact conn ccted with one terminal of an electric circuit including the signal or alarm mechanism, of two concentric spiral thermostats connected with opposite terminals of said electric circuit and of different resistance, substantially as set forth, for the purpose specified.

5. In an electric signaling apparatus, the combination with a signal or alarm mechanism, a relatively stationary contact connected with one terminal of an electric circuit inclu ding the signal mechanism, of a thermostat connected with the other terminal of the electric circuit and having contacts 2', i, on opposite sides thereof, that at t' being adapted to contact with the relatively stationary cont-act, and a second thermostat, more sensitive than that aforesaid, connected with the same terminal of the electric circuit as the relatively stationary contact and adapted to contact with the adjacent contact 1T, on the first thermostat, substantially as set forth.

0. A thermostat comprising two parallel expansible bars of different strength, and each adapted to be connected with one terminal of an electric circuit, and a relatively stationary contact arranged in the path of one of said bars and adapted to be connected with one terminal of an electric circuit, substantially as set forth.

7. A thermostat consisting of two concentrically-arranged spirally-formed expansible members insulated from each other and each adapted to be connected with one terminal of an electric circuit, and a movable graduated plate electrically connected with one of said expansible members and carrying a contact which extends into the path of the other of said expansible members, the two members being of dill'erent resistances, substantially as set forth.

8. In an electric signaling apparatus, the combination of two expansible bars of different resistance arranged to move through intersecting paths, signaling mechanism, electric circuits including the signaling mechanism and said expansible bars, and a relatively stationary contact connected with one terminal of one circuit and arranged in the path of one of the expansible bars, substantially as set forth.

In testimony whereof I athx my signature in presence of two witnesses.

IIOSEA I ltIAXIM.

Witnesses: V

Josurn B. IIECHT, HENRY A. BISCHOFF. 

